Can be private: simplification

Related to KT-22030

idea/src/org/jetbrains/kotlin/idea/inspections/MemberVisibilityCanBePrivateInspection.kt

@@ -32,13 +32,12 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithVisibility
 import org.jetbrains.kotlin.descriptors.EffectiveVisibility
 import org.jetbrains.kotlin.descriptors.effectiveVisibility
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
 import org.jetbrains.kotlin.idea.core.isInheritable
 import org.jetbrains.kotlin.idea.core.isOverridable
 import org.jetbrains.kotlin.idea.core.toDescriptor
-import org.jetbrains.kotlin.idea.intentions.getCallableDescriptor
 import org.jetbrains.kotlin.idea.quickfix.AddModifierFix
 import org.jetbrains.kotlin.idea.refactoring.isConstructorDeclaredProperty
-import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.search.isCheapEnoughToSearchConsideringOperators
 import org.jetbrains.kotlin.idea.search.usagesSearch.dataClassComponentFunction
 import org.jetbrains.kotlin.idea.search.usagesSearch.descriptor
@@ -47,7 +46,6 @@ import org.jetbrains.kotlin.idea.util.isExpectDeclaration
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
-import org.jetbrains.kotlin.resolve.DescriptorUtils
 
 class MemberVisibilityCanBePrivateInspection : AbstractKotlinInspection() {
 
@@ -126,10 +124,9 @@ class MemberVisibilityCanBePrivateInspection : AbstractKotlinInspection() {
             }
             val classOrObjectDescriptor = classOrObject.descriptor as? ClassDescriptor
             if (classOrObjectDescriptor != null) {
-                val receiver = usage.getStrictParentOfType<KtQualifiedExpression>()?.receiverExpression
-                val receiverDescriptor = (receiver?.getCallableDescriptor()?.returnType?.constructor?.declarationDescriptor
-                        ?: (receiver?.mainReference?.resolve() as? KtClassOrObject)?.descriptor) as? ClassDescriptor
-                if (receiverDescriptor != null && DescriptorUtils.isSubclass(receiverDescriptor, classOrObjectDescriptor)) {
+                val receiverType = (usage as? KtElement)?.resolveToCall()?.dispatchReceiver?.type
+                val receiverDescriptor = receiverType?.constructor?.declarationDescriptor
+                if (receiverDescriptor != null && receiverDescriptor != classOrObjectDescriptor) {
                     otherUsageFound = true
                     return@Processor false
                 }

idea/testData/inspectionsLocal/memberVisibilityCanBePrivate/sameClassFunctionCall.kt

@@ -0,0 +1,7 @@
+open class A {
+    <caret>internal fun foo() {}
+
+    fun bar(a: A) {
+        a.foo()
+    }
+}

idea/testData/inspectionsLocal/memberVisibilityCanBePrivate/sameClassFunctionCall.kt.after

@@ -0,0 +1,7 @@
+open class A {
+    private fun foo() {}
+
+    fun bar(a: A) {
+        a.foo()
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -2549,6 +2549,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/memberVisibilityCanBePrivate/JvmFieldOnProperty.kt");
         }
 
+        @TestMetadata("sameClassFunctionCall.kt")
+        public void testSameClassFunctionCall() throws Exception {
+            runTest("idea/testData/inspectionsLocal/memberVisibilityCanBePrivate/sameClassFunctionCall.kt");
+        }
+
         @TestMetadata("subClassFunctionCall.kt")
         public void testSubClassFunctionCall() throws Exception {
             runTest("idea/testData/inspectionsLocal/memberVisibilityCanBePrivate/subClassFunctionCall.kt");